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12:07 AM
TIL about braess's paradox
Braess's paradox (often cited as Braess' paradox) is a proposed explanation for the situation where an alteration to a road network to improve traffic flow actually has the reverse effect and impedes traffic through it. The paradox was postulated in 1968 by German mathematician Dietrich Braess, who noticed that adding a road to a congested road traffic network could increase overall journey time, and it has been used to explain instances of improved traffic flow when existing major roads are closed. The paradox may have analogies in electrical power grids and biological systems. It has been suggested...
when things like shutting down a road for repairs actually betters traffic
@cairdcoinheringaahing looks like REPL to me, just a weird version of it
 
@Riker Interesting
> If the latency functions are linear, adding an edge can never make total travel time at equilibrium worse by a factor of more than 4/3.
I wonder how that was proved
 
12:23 AM
 
12:56 AM
CMC (Python): golf: range(a,a+min(b-a, 2))
basically range from a to b with length of at most 2
 
@Downgoat [a]+[a+1][b-a<2:]
wait, do you have to handle a==b?
 
yes
 
@Downgoat [a,a+1][:b-a] (also shorter)
 
 
5 hours later…
6:07 AM
I just thought of a challenge that I don't have the time to write up completely, so I'll just describe it here: Check out the given commit of a non-packed ""git"" repository

probably with some modifications to the commit and tree format to make them easier to parse
so the challenge is mostly around correctly handling the file manipulations - open, create, and copy
 
 
2 hours later…
7:48 AM
Does anyone know a python library for outputting diffs in a patch file format?
You know, like @@157 +23, -18, that sort of stuff
 
-1
A: We're no strangers to code golf, you know the rules, and so do I

agantan ";$o=" We've known each other for so long Your heart's been aching but You're too shy to say it Inside we both know what's been going on We know the game and we're gonna play it ";$p="(Ooh, $z)";$r="($z)";$g=" how I'm feeling";$s="$n give, $n give";$t="I just wanna tell$l$g Gotta make$l underst...

Delete pls
 
8:39 AM
^ done
 
 
1 hour later…
9:39 AM
0
Q: ⡯⢰⢵⢸⣸⢈⢎⠀⣟⡆⡯⡂⡮⡆⡇⣇⢸⡀⣟⠀

ngn⢣⠃⢎⠆⣇⡇⡯⡂⠈⡏⢰⢵⢐⡭⢸⠪⡀⢸⢐⡭⠀⢹⠁⢎⠆⢸⣱⢸⡃⢎⠰⡱⢸⣱⢸⡃⠈⡏⢸⡃⡱⡁⢹⠁⢸⡀⡇⡗⢅⢸⡃⠈⡏⢸⢼⢸⢐⡭⠀ ⣇⢸⡃⢹⠁⢹⠁⣟⢸⢕⢐⡭⠀⡮⡆⡯⡂⣟⠀⡯⠰⡱⢸⣸⢸⢕⠀⣏⡆⢎⠆⢹⠁⣪⠅⢸⢼⢸⠰⣩⢸⢼⠀⡮⡆⡗⢼⢸⣱⠀⢎⠆⡯⠀⢇⠇⡮⡆⡯⡂⡇⡮⡆⣟⡆⣇⢸⡃⠸⡰⡸⢸⢸⣱⠈⡏⢸⢼⠀ ⢎⠆⡗⢼⢸⡃⢸⡃⡗⠔⡇⡯⠂⢹⠁⢣⠃⠸⡸⢸⡃⡯⡂⢹⠁⡇⢎⢰⢵⢸⡀⢸⡀⡇⡗⢼⢸⡃⢐⡭⢸⡃⡯⠂⡮⡆⡯⡂⡮⡆⢹⠁⣟⢐⡭⠀⢎⢸⢼⢰⢵⢸⢕⢰⢵⠰⡁⢹⠁⣟⢸⢕⢐⡭⠀ ⡮⡆⢐⡭⢸⠕⢰⢵⠰⡁⣟⠀⡇⣪⠅⢈⣝⢸⡃⡯⡂⢎⠆⠸⡰⡸⢸⢸⣱⠈⡏⢸⢼⠀ ⣪⠅⢎⠆⢸⠈⡏⠀⣇⠰⡱⠰⡱⢸⠪⡀⣪⠅⢸⡀⡇⡗⢅⢸⡃⠸⡰⡸⠰⡱⢸⢕⢸⣱⢐⡭⠀⡮⡆⡯⡂⣟...

 
 
2 hours later…
11:51 AM
@NewMainPosts Damn that's hard to read
 
12:16 PM
@NewMainPosts ..well I tried to do it in APL. Got the letters split up, but can't figure out a good matrix to char conversion.
 
@dzaima Did you look at the related APL solutions‌​?
@dzaima Once you have a Boolean matrix for a line, you just need to split on ∧⌿.
 
@Adám I can't figure out a good way to split though
 
@dzaima If m is a 4-row, n-column matrix with 1s for white and 0s for dots, then (∧⌿⊂⊢)1,m splits into letters with 1-column margin on the left.
 
12:33 PM
would A002183 work as a challenge
 
@Adám oh wow that's golfy. Way better than my 33 bytes..
Oh, is a thing I didn't know about
 
 
1 hour later…
1:39 PM
0
Q: Can we revive The Programming Language Quiz?

caird coinheringaahingThe Programming Language Quiz was a Cops and Robbers challenge posted 2 years ago, where users were challenged to create obfuscated Hello, World! programs, and others tried to identify the language(s) in which those programs worked. The post is currently closed to new cops submissions (although ...

 
2:38 PM
0
A: Sandbox for Proposed Challenges

flawrInside or Outside? code-golfgeometrypolygondecision-problem Given a point and a polygonial loop that is not self intersecting, determine whether the point is strictly inside or outside of the loop. Details The input is given as an ordered list of points in integral cartesian coordinates. You ...

 
3:25 PM
@dzaima It will be the first thing we'll address in Wednesday's APL learning session.
 
4:01 PM
Anyone know how to match anything except a certain substring in Python regex? Similar to [^<char>] but for multiple characters?
 
Not easy.
Turns out it is easier than I thought.
3206
Q: Regular expression to match a line that doesn't contain a word?

knaserI know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, I'd like to know if it's possible to match lines that don't contain a specific word (e.g. hede) using a regular expression. Input: hoho hihi haha hede Code: grep "<Regex for 'doesn't...

Actually I've read the question before, but I was impressed by the comment stackoverflow.com/questions/406230/…
 
@user202729 Hmm, I think the problem with that comment/regex is that it's quite specific to the question
@user202729 Thanks!
 
@cairdcoinheringaahing But you can extend that to any string. (basically unreadable)
But that seems to be wrong. Let me check. EDIT stackoverflow.com/questions/406230/… → it is indeed wrong.
 
@cairdcoinheringaahing Use your hands, not ur eyes. :P
4
Q: BigNum Bakeoff Reboot

Simply Beautiful ArtSome of you may be familiar with the BigNum Bakeoff, which ended up quite interestingly. The goal can more or less be summarized as writing a C program who's output would be the largest, under some constraints and theoretical conditions e.g. a computer that could run the program. In the same spi...

^ Anyone feel this is worthy to reopen may, um, vote on it I guess
 
4:21 PM
@SimplyBeautifulArt are you the owner of that wiki
 
I'm the owner of that challenge/question
 
@SimplyBeautifulArt I'm referring to the googology wiki
 
Oh
No, definitely not.
The founder is mentioned on the blog of "googology people" if you want me to look it up
 
I realize that it is a community effort, but I think you know what I mean :) Alright, no need; I was only curious
 
:P
I am a user on the wikia though
 
4:24 PM
Are you a student?
 
Uh, yeah
I'm <18 years old
 
ah, ok; well, hopefully you are considering studying math in the future. I don't know whether you proved any of the relations such as (Loader's number > TREE(3))
 
Dats easy
 
I didn't read the details, but some of those sorts of things are nontrivial
 
Just prove that TREE(n) can be approximately created in the calculus of constructs
Similar to the bottom-up method for approximating the Busy Beaver function.
 
4:30 PM
Ah, yeah, so I suppose it beats TREE(3) pretty badly. The thorny relations I remember are when two people build two different fast-growing functions and you have to compare values. Like up-arrow vs. right-arrow big numbers.
 
Meh
Everything's generally not too bad when you use the fast-growing hierarchy, which allows for quick approximations of very big numbers
Beats TREE(3) like, you don't even know how badly
x.x
Beats it so badly that any Loader's number type programs will be called "Extremely large with unknown limit"
 
I mean, I hadn't read the full definition of the sequence. I'm not familiar with the calculus of constructs, but I get the point
 
:P I actually don't understand the calculus of constructs, nor do I understand TREE(3). I just understand the fast growing hierarchy enough to know its pretty bad.
 
I'm interested in a few of the things at the lower levels of the hierarchy (the busy beaver numbers, for example), but that's about as far as my really serious interest goes.
 
Yeah, understandable.
Busy beaver numbers are actually beyond the hierarchy completely btw
@EricTressler Nope, but I can approximate Graham's number in the fast growing hierarchy
 
4:37 PM
Are they? Oh, of course, they are by definition at least as big as any program you can write, etc. I don't have the familiarity required to keep all of that straight
 
Anyway, I studied Ramsey theory and some related things, which mostly involves very small numbers (though Graham's number is an upper bound for a Ramsey-theoretic function)
 
Graham's number ~ f_(ω+1)(64)
Which is smaller than all of the current scores on my challenge
 
What is f_? And, is the "~" informal, or are you saying specifically that it's between f_(ω+1)(63) and f_(ω+1)(65)?
 
~ approximately
IIRC Graham's number is between f_(ω+1)(64) and f_(ω+1)(65)
@EricTressler f_x(n) is a function of n.
And a hierarchy of x.
 
4:41 PM
It's an interesting use of ~ to mean that they could differ by some incomprehensible number of orders of magnitude
 
Nah, definitely not incomprehensible.
Would you like to continue this chat here? or there?

 Ordinality?

Trying to understand extraordinarily large numbers.
 
4:52 PM
Does anyone here use Linux w/ 4K/HiDPI?
 
 
2 hours later…
6:32 PM
0
A: Sandbox for Proposed Challenges

Jonathan S.There's no such thing as a "half empty glass" code-golf ascii-art You probably know the rhetorical question of whether a glass is half full or half empty. I'm getting a little tired of the phrase, so I decided that it's time to eliminate this confusion about glass fullness or emptiness programm...

 
@LuisMendo Don't you think would fit rather than one of those tags?
 
3
Q: Minimal sparse rulers

Luis MendoA standard ruler of length n has distance marks at positions 0, 1, ..., n (in whichever units). A sparse ruler has a subset of those marks. A ruler can measure the distance k if it has marks at positions p and q with p−q=k. The challenge Given a positive integer n, output the minimum number of ...

 
6:47 PM
@Mr.Xcoder Good idea. Done
 
 
2 hours later…
8:55 PM
Amazing how during the weekend everyone here is inactive
 
"inactive"
 
@Christopher2EZ4RTZ Makes sense. Most people have lives or things to do on the weekend :P
 
@cairdcoinheringaahing shouldn't we be doing school during the school week
 
@Christopher2EZ4RTZ People our age, yes. But a lot of people here have jobs, and go on TNB at work
 
@cairdcoinheringaahing shouldn't we be working at work?
 
8:59 PM
@Christopher2EZ4RTZ ¯\_(ツ)_/¯ I don't have a job, so IDK
 
@cairdcoinheringaahing i guess
 
-1
Q: Voronoi graph from image

FrancisI'm trying to find all the neighbors of a given cell in a voronoi diagram. For example, given the following diagram, if I want to find the neighbors of the cell 1, then I should be able to return the points 2, 3 and 4. I only have the image (pixels with position and colors), not the graph itse...

 
I most definitely tnb at work
 
9:14 PM
"work"
 
My boss thinks it’s work and that’s what counts
I don’t start uni till feb, then I’ll be tnbing at school
 
@ATaco wait
ohh]
i thought you meant you don't start school (like high school) until feb
lol
I need help. All the new challenges are tough and I don't understand them. I just lost it. Right now I can't answer any new challenges. I want to but I just can't do it. I have not gained rep here for a long time. Anyone have ideas for easy challenges to answer?
No rep pretty much since september
 
write a challenge?
 
I suck at that
 
9:27 PM
@Christopher2EZ4RTZ What language do you normally use?
 
@cairdcoinheringaahing Processing.js off khanacademy
or whatever eso lang i find that works
I also dabble in brainflak
 
@Christopher2EZ4RTZ In that case, I'd recommend learning a golfing language, such as Jelly, or use a language that not many other people use. A good way to get rep is to answer in a language others use, as they'll upvote your answer
 
What's the tag for a question where the state must be saved between runs?
Something along the lines of stately...
Or was that just something proposed on meta that never got added
 
Don't think we have one for that
 
-1
Q: Generate a Texting Dictionary

Christopher 2EZ 4RTZOld fashioned cell phones were and are used heavily as texting platforms, unfortunately the keyboard has only 12 + a few buttons, and is therefor ill-suited to naive text entry. Common solutions make use of the traditional telephone coding (generally with a modest extension for 'q' and 'z'): 2:...

 
9:34 PM
It's a great idea though
 
Anyone want to answer that ^^
I only have one answer and I felt it was a good challenge
 
TFW The chat bot account you made got more rep this week than you :/
 
@cairdcoinheringaahing o.o
 
9:35 PM
It was suggested but never actually made.
Someone should...
 
Yep, seems like a consensus to me
Heh, I'd already voted on both the question and the answer...
 
9:48 PM
my phone spazzed out and clicked a bunch of random things >_< if something was flagged blame iphone
 
2
Q: Normalize a Vector

FlipTackTo normalize a vector is to scale it to a length of 1 (a unit vector), whilst keeping the direction consistent. For example, if we wanted to normalize a vector with 3 components, u, we would first find its length: |u| = sqrt(ux2 + uy2 + uz2) ...and then scale each component by this value t...

 
10:16 PM
@StewieGriffin & with | selects the two-input version (2 is the the second input, which indicates which norm to use). I don't see any shorter way, good job!
 

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